Back for swivel chair



FIG. 1 is a rear elevational view of a back for swivel chair showing my new design.

FIG. 2 is a top plan view thereof.

FIG. 3 is a right side elevational view thereof.

FIG. 4 is a left side elevational view thereof.

FIG. 5 is a front elevational view thereof.

FIG. 6 is a perspective view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawings depict environmental structures and form no part of the claimed design. 

The ornamental design for a back for swivel chair, as shown and described. 